You get a square number by multiplying a number by itself, so knowing the square numbers is a handy way to remember part of the multiplication table. Although you probably remember without help that 2[more…]

A prime number can be divided by only itself and 1. This makes it stubborn. Like certain people you may know, a prime number resists being placed in any sort of a box. Look at how the number 13 is depicted[more…]

An important addition to the number line is the number 0, which means nothing, zilch, nada. Step back a moment and consider the bizarre concept of nothing. For one thing — as more than one philosopher[more…]

Suppose you start at 0 and circle every other number on a number line, as shown in the below figure. As you can see, all the even numbers are now circled. In other words, you’ve circled all the multiples[more…]

It is important to know when a zero is a placeholder, and when it is a leading zero. Although the digit 0 adds no value to a number, it generally acts as a placeholder to keep the other digits in their[more…]

When you write a long number, you use commas to separate periods. Periods are simply groups of three numbers. They help make long numbers more readable. For example, here’s about as long a number as you’ll[more…]

If you know how to round numbers, you can use this skill in estimating values. Estimating saves you time by allowing you to avoid complicated computations and still get an approximate answer to a problem[more…]

When you want to add large numbers, you can stack them on top of each other so that the ones digits line up in a column, the tens digits line up in another column, and so on. You then add column by column[more…]

Sometimes, when you are subtracting large numbers, the top digit in a column is smaller than the bottom digit in that column. In that case, you need to borrow from the next column to the left. Borrowing[more…]

Each of the Big Four operations (addition, subtraction, multiplication, division) has an inverse — an operation that undoes it. Addition and subtraction are inverse operations because addition undoes subtraction[more…]

Addition and multiplication are both commutative operations. Commutative means that you can switch around the order of the numbers without changing the result. This property of addition and multiplication[more…]

Addition and multiplication are both associative operations, which means that you can group them differently without changing the result. This property of addition and multiplication is also called the[more…]

In math, distribution (also called the distributive property of multiplication over addition) allows you to split a large multiplication problem into two smaller ones and add the results to get the answer[more…]

The ideas of equality, expressions, and evaluation are vital concepts when working with equations.An equation is a mathematical statement that tells you that two things have the same value — in other words[more…]

In math, parentheses — ( ) — are often used to group together parts of an expression. This helps you to find the order of precedence when you work with equations. When it comes to evaluating expressions[more…]

When you write out a word equation, you have the facts you need in a form you can use to find the solution. You can often solve the problem by plugging numbers from one word equation into another. The[more…]